@node setenv, environment
@subheading Syntax

@example
#include <stdlib.h>

int setenv(const char *name, const char *value, int rewrite);
@end example

@subheading Description

This function sets the environment variable @var{name} to @var{value}.
If @var{rewrite} is set, then this function will replace any existing
value.  If it is not set, it will only put the variable into the environment
if that variable isn't already defined.

@subheading Return Value

Zero on success, -1 on failure.

@subheading Portability

@portability !ansi, !posix